Commit 9ba33339 authored by Roi Dayan's avatar Roi Dayan Committed by Saeed Mahameed
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net/mlx5e: Avoid false lock depenency warning on tc_ht



To avoid false lock dependency warning set the tc_ht lock
class different than the lock class of the ht being used when deleting
last flow from a group and then deleting a group, we get into del_sw_flow_group()
which call rhashtable_destroy on fg->ftes_hash which will take ht->mutex but
it's different than the ht->mutex here.

======================================================
WARNING: possible circular locking dependency detected
5.11.0-rc4_net_next_mlx5_949fdcc #1 Not tainted
------------------------------------------------------
modprobe/12950 is trying to acquire lock:
ffff88816510f910 (&node->lock){++++}-{3:3}, at: mlx5_del_flow_rules+0x2a/0x210 [mlx5_core]

but task is already holding lock:
ffff88815834e3e8 (&ht->mutex){+.+.}-{3:3}, at: rhashtable_free_and_destroy+0x37/0x340

which lock already depends on the new lock.

Signed-off-by: default avatarRoi Dayan <roid@nvidia.com>
Signed-off-by: default avatarSaeed Mahameed <saeedm@nvidia.com>
parent 84db6612
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+12 −0
Original line number Diff line number Diff line
@@ -190,6 +190,14 @@ struct mlx5e_tc_attr_to_reg_mapping mlx5e_tc_attr_to_reg_mappings[] = {
	[NIC_ZONE_RESTORE_TO_REG] = nic_zone_restore_to_reg_ct,
};

/* To avoid false lock dependency warning set the tc_ht lock
 * class different than the lock class of the ht being used when deleting
 * last flow from a group and then deleting a group, we get into del_sw_flow_group()
 * which call rhashtable_destroy on fg->ftes_hash which will take ht->mutex but
 * it's different than the ht->mutex here.
 */
static struct lock_class_key tc_ht_lock_key;

static void mlx5e_put_flow_tunnel_id(struct mlx5e_tc_flow *flow);

void
@@ -5215,6 +5223,8 @@ int mlx5e_tc_nic_init(struct mlx5e_priv *priv)
	if (err)
		return err;

	lockdep_set_class(&tc->ht.mutex, &tc_ht_lock_key);

	if (MLX5_CAP_FLOWTABLE_NIC_RX(priv->mdev, ignore_flow_level)) {
		attr.flags = MLX5_CHAINS_AND_PRIOS_SUPPORTED |
			MLX5_CHAINS_IGNORE_FLOW_LEVEL_SUPPORTED;
@@ -5333,6 +5343,8 @@ int mlx5e_tc_esw_init(struct rhashtable *tc_ht)
	if (err)
		goto err_ht_init;

	lockdep_set_class(&tc_ht->mutex, &tc_ht_lock_key);

	return err;

err_ht_init: